A treatment method for allowing cut flowers of roses and the like to be kept appearing like natural flowers for a long period of time for the purpose of decoration is proposed, for example, in JP4-505766T2.
In this treatment method, the water in the cell tissue of cut flowers, i.e., tissue water is removed together with the coloring matter, and polyethylene glycol is allowed to permeate into the tissue once filled with tissue water, then a coloring matter being added for dyeing. The method treats the cut flowers generally through a dehydration step, permeation step and drying step.
In the dehydration step, cut flowers are immobilized in a container that has a molecular sieve spread all over its bottom and is filled with a dehydrating solvent lower in specific gravity than water, for example, an anhydrous organic solvent such as acetone.
In this step, the water in the tissue of cut flowers, i.e., tissue water is gradually dissolved into a dehydrating solvent, and simultaneously, the dehydrating solvent migrates into the tissue. So, in the cut flowers, while the tissue of cut flowers maintains its mechanical structure, the dehydrating solvent gradually replaces the tissue water, to remove it.
In the permeation step, the cut flowers are immobilized in a container filled with a permeating solution prepared by dissolving polyethylene glycol destined to permeate into the leaves, into a mixture consisting of acetone and a cellosolve. In this case, the polyethylene glycol is a mixture of polyethylene glycols adequately different in molecular weight.
In this case, in the conventional practice, a dye such as a woven fabric dye for acrylic fibers is mixed in the permeating solution, for allowing the coloring matter to permeate into the tissue of cut flowers together with polyethylene glycol, for dyeing.
After a predetermined time has elapsed in the permeation step, the permeating solution is discharged, and the cut flowers are dried in the subsequent drying step, to complete the preservation treatment of cut flowers. The cut flowers treated like this are packed in a basket or the like together with leaves for offering as merchandise.
The leaves packed with cut flowers are generally thicker than petals, and their nerves act as barriers. So, depending on leaf properties (thickness, hardness, color and the like of leaves), it can happen that dehydration cannot be achieved perfectly, and chlorophyll cannot be dissolved out sufficiently to pose a problem that the color cannot be perfectly removed.